1. Field of the Invention
The invention relates generally to wireless communication and more particularly to systems and methods for voice buffering in wireless communication.
2. Background
Wireless communication device users are demanding faster and faster connection times. Instant connectivity is the goal. Push to talk (PTT) communications are one method of reducing delays in wireless communications, especially in cellular communications, such as communication by cellular telephone (also known as cell phones). In PTT communications, the user merely has to push a button on the cell phone to be connected with another person by cell phone. The other person does not have to hear a ring or even answer the cell phone. In other words, the cell phones can be configured to be automatically connected, without any intervention by the receiving party. PTT systems are described further in U.S. patent application Ser. No. 10/903,174 “CALL PROCESSING SYSTEM AND METHOD”, filed on Jul. 30, 2004, by Murtuza Chhatriwala and Joseph Giacalone, which is hereby incorporated herein by reference.
PTT communication is typically faster than standard cell phone communications. However, many PTT users want even shorter call set-up times. Call set-up time can be can be between five and 20 seconds, or more. Delays between initiating a push to talk (PTT) session and the time when the initiator is allowed to begin speaking are frustrating to PTT wireless communication device users.
In voice over internet protocol (VoIP) PTT systems, the problem is solved by buffering the audio data (e.g., voice) in a memory buffer while waiting for the call to set up. One problem with buffering in a voice over voice channel (VOVC) is that traditionally, at the time of completion of the set-up of a VOVC call, commands are sent to initialize the vocoder on the wireless communication device. Buffering audio works smoothly in VoIP systems, among other reasons, because the set-up of a data call does not trigger initialization of the vocoder.
Other problems with buffering in a VOVC relate to receiving incoming messages such as other PTT calls and normal voice calls. Again, buffering in a VoIP call works smoothly, because normal VoIP calls do not allow incoming calls such as other PTT calls and normal voice calls. Thus, voice buffering can be added to VoIP calls smoothly without problems caused by other incoming messages, such as other PTT calls and normal voice calls.